Feeding device



April 21, 1942. v. E. MccoY 2,280,656 FEEDING DEVICE l Filed MaIOh 3, 1939 4 Sheets-Sheet l Apri121 ,1942.

FEEDING DEVICE Filed March 3, 1939 4 sheets-sheet 2A v. E. MccoY 2,2805656 April 21, 1942. v E, MCCOY 2,280,656

- FEEDING DEVICE Filed March 3, 1959 4`Sheets-Sheet 3 April 21, 1942. v. E. Mccy 2,280,656

FEEDING DEVICE Filed March 3, 1939 4 Sheets-Sheet 4 v jatented pr. 21, 1942 Verl E. McCoy,

La Grange, Ill., assigner to National Aluminate Corporation, Chicago, corporation of Delaware Ill., a

Application March 3, 1939, Serial No. 259,519 13 Claims. (Cl. liti-165) This invention relates to an automatic solution feeding apparatus and more particularly to a proportional feeding system and pump therefor arranged to feed one or more fluids or solutions into another fluid in substantially direct-V proportion to the ilow of the last named fluid in a suitable conduit.

The invention may also be used accurately to proportion the input of chemical solution into direct proportion to the iiuid` a storage tank in directed into or withdrawn from the storage tank.

This application is a continuation in part of my prior application Serial No. 172,687, filed November 4, 1937, now Patent No. 2,252,939,;

granted August 19, 1941.

It is one object of the invention to provide new and improved means for proportionally feeding a solution into a pressure conduit or the like in substantially direct proportion to ume flow of the fluid in said conduit. Heretofore, attempts have been made to use a differential pressure in the fluid system produced by a Venturi tube or other device providing a vena contracta. However, the differential pressure produced in such a manner does not vary directly with the velocity oi the flow, but varies more nearly as the square of the velocity so that, when such devices are used, there is a wide variation in the feed which is not directly proportional to the volume ilow in the system.

Proportional pumps have also been used for introducing a solution into a fluid. However, many diiiiculties have been encountered in that these pumps are not constructed for accurate-- substantially in direct proportion to the volume flow. It will be understood, of course, that, while the pump may accurately be controlled by velocity or volume ow in a conduit, the pump may discharge either into the conduit against pressure therein or into a storage tank. In fact, the output of the pump may be directed in any manner desired, but will always be proportional to the vol-z f the velocity flow or the volume flow through the controlling conduit.

it is also an object to provide in a system of the character described a variable proportional pump having an automatic electrical control means and means for operating the electrical control in direct relationship to the velocity flow of the fluid in a suitable conduit.

A further object is the provision of a proportional pump which may intermittently be operated from a continuous power source through an adjustable harmonic transmission and wherein the capacity of the pump may easily be predetermined at any Value over a wide range.

A further object is the provision of an adjustable pump having .new and novel structural details whereby the pump may be controlled by the uid velocity to operate intermittently, with an output always proportional to the volume ow of the fluid within the entire adjustable range of the pump and may operate continuously with a predetermined output in accordance with a predetermined fixed Velocity.

Further objects will be apparent specification and the appended claims.

In the drawings:

Fig. 1 is a iront view of the proportioning pump taken from the end on which the pump cylinders are mounted. f

Fig. 2 is a perspective side View of the embodiment illustrated in Fig. l.

Fig. 3 is a fragmentary perspective view from the opposite side of the pump from that shown in Fig. 2.

Fig. 4 is an axial sectional View through the electrically controlled clutch mechanism for causing either intermittent or continuous operation of the pump.

Fig. 5 is a transverse sectional View taken on a line substantially corresponding to line 5-5 of Fig. 4.

Fig. 6 is a digrammatic viewof the electrical control system whereby the pump may be operated in accordance with the velocity flow of fluid in a conduit.

Fig. 7 is a diagrammatic View of one of the pump discharge outlets and illustrates the connections whereby a single opening maybe used for inlet and outlet for any of the pump cylinders.

Fig. 8 is a diagrammatic View illustrating another embodiment of the electrical control system for a proportional pumping means.

Referring to the drawings in detail, the pump embodiment illustrated in Figs. 1 to 5, inclusive.

from the comprises a base I having upright columns 2 thereon on which is supported a rectangular frame 3 having vertically positioned parallel guide rods 4 mounted therein. A vertically slidable carriage or crosshead 5 is supported on these guide rods for vertical sliding movement and is provided with a transverse slot 5 in which is positioned a bearing block 'l for transverse sliding movement in the slot 6. The block l is pivoted at 8 (Fig. 1) on an adjustable member 9 (Figs. 2 and 3). The member 9 is slidably mounted on a transverse arm or lever IU, the arm being pivoted at II on the frame 3. The slide member 9 extends rearwardly of the lever I0, as shown in Fig. 3, and is provided with a dthreaded connection to a complementarythreaded rod I2. This rod i2 is parallel with the lever IllY and is supported for rotation in a bearing Ilia-adjacent the pivoted end of the lever I3 and is-provided with a handle I3 whereby it may be rotated to lposition the member S as desired on the lever I0, thereby similarly positioning the block 'I in the slot 6 of the carriage 5.

A connecting rod I4 is pivctally connected to the lever I at I5 and the opposite end of the connecting rod is pivotally secured to a crank pin "I6 (Fig. 1), which latter is mounted on an eccentric disc Il as shown. The eccentric I 'I is secured to a driven shaft I8 (Fig. 4) so that, whenever the driven shaft is rotated, the lever I0 will be oscillated to vertically oscillate the carriage by means of the sliding block connection previously described. The movement of the carriage will be limited by the adjusted position of the block I on the lever I0.

A compression spring I9 is positioned between the slide frame 5 and the upper portion of the fixed frame 3 in order to prevent any lost motion in the operating parts and to provide smooth and vibrationless operation. The eccentric is for the purpose of operating an oil pump which is provided with a spring pressed vertically movable plunger 2l in contact with the surface of the eccentric and operated thereby. In other words, the eccentric provides a cam surface for operation of the pump during each revolution of the drive shaft I8. The function of the oil pump is to pump oil to allY moving parts-of the device and individual conduits may be used to 'deliver the oil to all points of possible wear. These conduits may be provided in-r any suitable manner and are not shown, as they form no part'of the present invention.

As previously stated, the eccentric I'I is secured to a driven shaft I8 which is; mounted in suitable bearings 22 and may be intermittently or continuously driven from a suitable power source such as an electric motor 23 having its drive shaft 24 in alignment with the driven shaft I8. A connection between the drive shaft 24 and the driven shaft I8 is provided by means of a suitable clutch 25. This clutch comprisesfa driving member 26 having suitable jaws; thereon, as shown particularly in Fig. 2, and co-operating with comx plementary jaws on a driven member 21 slidably mounted on the shaft I8 by means of a feather key 28. The driven member 27 is provided with a groove 29 arranged to receive pins or rollers 30 on a control yoke lever 3| pivoted at 32.

It will be obvious that, by movement of this lever 3I, the driven member 21 may be made to slide on the shaft I8 and into or out of engagement with the driving member 26. A bolt 33 is threadedinto the endof the driven-shaft I8 and provided with a washer34 Aadjacent* the head of the bolt and an enlarged washer 35 engaging the driven member 21, A spring 36 between these Washers tends to normally return the driven member 21 out of engagement with the driving member 25 whenever the lever 3i is released so that it may automatically move to the dotted line position shown in Fig. 4.

As shown in Fig. 2, the lever 3l is connected to the armature 31 of a solenoid 38 in such a manner that, Whenever the solenoid is energized, the lever 3| will be moved from the dotted line position shown in Fig. 4 to the full line position 4to thereby cause engagement of the clutch and drive the previously described pumping mechanism. The solenoid 38 may automatically be controlled by the velocity flow in a fluid conduit in a manner which will be later described.

The-carriage 5 of the pump mechanism is provided with a centrally positioned, forwardly extending yoke 33 having a slot 40 therein, in which is engaged the slotted stem of a pump plunger 4I. Thispump plunger operates in a pump cylinder 42, which may be of the usual `type and provided'with a common inlet and discharge opening' 43. The cylinder'43 is mounted on the base I and may be provided with inlet and outlet connections, such as shown in'Ifig. 7, in which is shown an inlet conduit 44 connectedl to the cylinder 42'through a double acting check valve 45. The check valve 45 is arranged to enable fluid to be drawninto the cylinder through the inlet 44 and discharged through a conduit 43 having a check valve`4'I therein. The outlet conduit 46 may be provided with a so-called surge chamber 48 and a control valve 49.

The particular check valve arrangement shown in Fig. 7 is adapted to eliminate any airpockets in the check valves themselvesor in the connecting pipe which otherwise would act as a cushion on the pump plunger'and incertain cases might actually stop the pump from delivering due to alternately compressing and expanding this air.

The check valve assembly shown in Fig. 7 is effective in eliminating this diculty. The discharge valve 41 is mounted directly above the inlet check valve so that, if there is any discharge at all, the air is discharged rst through the check valve 41 and out into the discharge line 45. Once the air is discharged beyond the angle check valve 4l, it doesl not affect the operation of the pump. The air chambers 48 in the discharge line tend to smooth out the Adelivery from the single acting lpump at the point of final use. The arrangement illustrated prevents air being trapped in any position where it may be harmful to the operation of the pump.

The pumpcylinder 42 and the other cylinders disclosed herein may be provided with separate inlet and outlet openings, as shown in Fig. 7,

in 'which one of the openings is closed by means ofa threaded plug 43a. It will be understood that, while the conduit and valve'arrangement shown in Fig. 7 is preferred, any suitable arrangement may be provided by using one or both of the cylinder openings.

Ihe pump embodiment disclosed herein is adapted to pump three different chemicals at one time. rlhis is desirablewhere clarifying and softeningof water Ais being accomplished simultaneously. For this purpose, three pump cylinders are mounted on the base I, preferably in transverse alignment as shown in Fig. 1. A pump cylinder 5B is provided at' one side of the mainV cylinder 42 and is provided withr a plunger '5I havingany upwardly extended threaded stem .on the bearing 22.

52 Vwhich extends through a slot 53 in an outwardly extending yoke 54 forming a part of the carriage 5. The plunger is provided below the yoke with a stop nut 55 and above the yoke with adjustable stop nuts 56 on the stem 52. It will, therefore, be apparent that, by adjusting the position of the nuts 56 on the stem 52 and locking them in the usual manner, the stroke of the plunger 54 may be varied as desired and the output may be in a predetermined relationship to the output from the main cylinder 32.

On the opposite side of the main cylinder 42 is positioned a still smaller cylinder 51 having an associated plunger 51al with a vertical threaded stem 58 extending through a slot 53a in a yoke f1a on the carriage 5. This stem is also provided with a stop nut 59 and adjustable lock nuts 80 whereby the plunger stroke is adjustable in the same manner as the opposite plunger 5l. With this construction the stroke of each plunger may be predetermined for relative fluid discharge within the limits of adjustment of the machine.

In order to operate the pump intermittently or continuously in accordance with the velocity ow in a uid conduit and to provide one cycle of operation of the pump for each momentary energization of the solenoid 38, a star Wheel 6| is pivoted on a bearing bolt Sla extending from the driven shaft bearing 22. In Fig. 4, which illustrates this star wheel and associated clutch in detail, the clutch 25 is shown in engagement, that is, during a revolution of the driven shaft lt. The driven clutch member 21 is provided with a laterally extending pin or roller 52 which normally is engaged in a slot 63 in the bearing member 22 when the clutch is disengaged. However, when the solenoid 3S is energized, the lever is moved from the dotted line position in Fig. 4 to the full line position to thereby engage the clutch and simultaneously withdraw the pin 62 from the slot B3 to enable rotation of the driven shaft i8. During this rotation of the driven shaft i3, the pin 62 bears against the edge of the flange 22a o the bearing 22 to retain the clutch in engagement and, during each revolution, the pin engages one of the arms o the star wheel 6l and rotates the star wheel one-sixth of a revolution. The star wheel l is preferably provided with six points and six corresponding notches between the arms and into which the pin 52 may engage. The star wheel 6I is also provided with a three point cam 64 which is engaged by an electric switch arm 65 for operating a switch 65, which may also be mounted The switch B6 is a double throw switch for alternately connecting two ,branch circuits with a single conductor so that each revolution of the clutch reverses the switch connections. This is shown in Fig. 6. It will be apparent thaty with each consecutive engagement of the pin 62 with the star wheel 60, the switch arm 55 will alternately be moved from 'one position to another, whereby to control the operation of the pump.

Fig. 6 is a diagrammatic illustration of the electrical pump control whereby it may be operated in accordance with the velocity iow in a conduit 51. In this diagrammatic View, the solenoid 38 is arranged to control the engagement and disengagement of the clutch 25 in the manner previously described. In order to control the solenoid 38 so that the pump will intermittently be operated to inject solution into a conduit 61 proportional to the volume flow, an electric cir- --cuit is provided which comprises conductors 68 which may be connected to any suitable power source and are directly connected for operating the motor 23. These conductors are provided with an automatically controlled, double Apole switch 69 for starting and stopping the motor. For controlling the various operations, solenoids A, B, and C are connected in the circuit as shown. Solenoid A is normally de-energzed, but is intermittently energized simultaneously with the clutch controlling solenoid 38 in accordance with unit Volume flow in the conduit 61. Solenoid B is a normally energized time delay relay of well known type, so constructed and connected in the circuit that, when it is de-energized, the motor will start. It is normally energized by ymeans of the shunt circuit shown to maintain an open circuit for solenoid CJ which is thereby normally de-energized to hold the-motor circuit open. The solenoid A is wired in parallel with the clutch controlling solenoid 38 in a branch circuit comprising the conductors 10, 1|, and 12, and a two way switch 13 is provided in series with the two way switch (it controlled by the star wheel cam 64.

A meter is provided in the conduit 61 for controlling the operation of the switch 13 and comprises a propeller 1d connected through bevel gears 15 for rotation of a cam 16 to operate the switch 13 in accordance with the flow of fluid in the conduit 61. It will be apparent that current will flow through the conductor 10, 1I, and 12 only when the switches 66 and 13 are in corresponding relative positions to complete the circuit through conductor 1i), that is, either as shown in Fig. 6 or in the reverse position. When the switches are in the position shown, the solenoid A and the solenoid 38 will be energized, whereby the clutch 25 will be engaged to rotate the driven shaft and operate the pump through one cycle. During this cycle, the pin 52 will engage the star wheel 6l and reverse the position of the switch 66 so that the solenoids A and 38 will be cle-energized and the pin 62 will engage in the notch 63 and stop the pump after a single stroke and the pump will remain stationary until the switch 13 is reversed by the flow of iluid in the conduit 61. As previously stated, the solenoids A and 33 are simultaneously energized and the solenoid A is arranged to control a switch 13 in the circuit of the normally energized solenoid B. This solenoid B normally retains a switch 19 open in the circuit of the solenoid C, whereby the solenoid C is not energized. However, as soon as the solenoid A is energized, the break of the switch at 18 de-energizes the solenoid Band permits the spring pressed switch 19 to close the circuit of the solenoid C, which is arranged to control the motor line switch 59 through the solenoid C. Therefore, it will be apparent that, whenever the solenoids A and 33 are energized, the solenoid C will also be energized to close the motor circuit, which, due to the time del-ay action of the relay B, will remain closed for at least one cycle of the pump. The timing of the relay B is regulated from the last operation of solenoid A in all cases. If the contacts at the meter switch are suiciently frequent, the motor will run ccntinuously. Should the time interval between contacts be longer than that for which the timer B is set, the motor will stop until the meter switch makes another contact. In any event, the pump makes one complete cycle for each meter switch contact.

It will be understood, of course, that the various one or all of the pump cylinders may be made to discharge fiuid directly into the uid conduit 6l against the pressure therein or only one of these cylinders may discharge into the conduit and the other cylinders may be arranged to discharge into a reservoir or otherwise as predetermined. It will also be clear that one or more of the pump cylinders may be used, and, if the ow in the conduit 67 is continuous at anxed velocity, the pump may be adjusted for continuous operation if desired. Should the number of switch contacts made by the conduit low meter be suiciently great, the motor will continue to run steadily. Should the contact interval be longer than that for which the timing circuit is set, the motor will stop and remain stationary until the meter switch makes another Contact. In every case the pump itself makes one complete stroke for each reversal of the flow meter contacts.

Fig. 8 illustrates an embodiment in which a pump S is driven by means of a crank shaft 8?. as shown. This view is diagrammatic and is intended to represent an embodiment of the control mechanism which may be used in connection with the present pump or with any suitable type of pump. In this embodiment, the crank shaft 82 is driven through a suitable clutch 33 by means of a continuous running motor 8d and a speed reducing mechanism 85. The clutch 83 is normally disengaged and comprises a driving member 86 and a driven member 8l. The clutch is preferably of a type which may automatically be controlled to permit only one revolution when desired. In the embodiment illustrated, the clutch comprises the usualdog-controlled clutch in which the dog is provided with an outwardly extending arm 85:3 which normally rests on a detent lever Sii, which latter is retained against a stop il by means of a spring Si. In this position the clutch is disengaged.

In order to permit engagement of the clutch, a solenoid 92, which may correspond to the previously described solenoid 38, is provided with an armature 93 which is normally held in the position shown by means of a spring Srl. The armature is provided with a pawl 85 which is movable with the armature and which is provided with a slot Q5. When the solenoid 92 is energized, the pawl Q5 which engages the end ofthe detent 89 is moved by the armature to release the dog arm 88 and permit the engagement of the clutch. A xed pin 96a extends into the slot S6 and, during the movement of the pawl 95 to cause engagement of the clutch, the pawl is moved laterally to release the detent 89, which immediately returns to the position shown and disengages the clutch after a single revolution.

The solenoid 92 may be connected to a controlling switch 9'! by means of conductors 98 connected in series with a suitable power source. In this embodiment, the switch Si is pivoted at 9S and provided with an arm having a roller Itl thereon engaging a cam i Bi, this cam being driven from the propeller 'it through a transmission which may be similar to that shown in Fig. 5. The pump Sil is arranged to discharge into the conduit 6'! through a suitable discharge conduit i632 and the solution may be withdrawn from a chemical vat |93 through a suitable conduit H34.

As previously stated, the embodiment herein disclosed is designed to pump three different chemicals at one time. This is desirable for simultaneously clarifying and softening water. For instance, the large central plunger may pump the softening chemical, one of the outside plungers may pumpiron sulfate and the smaller plunger may pump sodium aluminate. In this instance, the chemicals pumped by the two small plungers are for clarification only. The proportioning may be on inflow to a reservoir, the pump being controlled by a ilow meter in a supply line to the reservoinalthoughthe chemical treatments may be added to the water at diierent points. The sodium aluminate plunger may be the smallest, as this chemical is required in the least quantity.

Predetermined proportioning may be accomplished by adjusting the length of stroke of the crosshead 5 by means of the adjusting screw I2 and handle I3. The center plunger is directly connected to the crosshead or carriage 5 and the two outside plungers are arranged to stroke either the full movement of the crosshead or less, according to the position of the adjusting nuts on the plunger stems. The diameters of the plungers and cylinders may correspond to requirements for adjustable relationship over a predetermined range with particular relation to the type of chemical used.

An important feature of the invention is the provision of an unintermitted adjustment whereby adjustment by infinitesimal increments may be made for all plunger strokes simultaneously in a predetermined relationship and this relationship may be varied by separate adjustment of individual plungers. This enables a selection of volume output relationships covering an extremely wide range.

Modications may be made without departing or aluminum sulfate,

from the spirit of the invention, and it is therefore desired that the invention be limited only by the prior art and the scope of the appended claims.

Having thus described this invention, what is claimed and desired to be secured by Letters Patent is:

1. In a iluid proportioning apparatus, the combination of a normally deenergized motor, a pump, a mechanism for connecting said motor and pump including a normally disengaged clutch, means to intermittently energize said motor and engage said clutch in synchronized response to unit volume flow of fluid in a conduit, means for predeterm-ining the running time interval of said motor for each clutch engagement, and means to retain said clutch engaged throughout a complete cycle of operation of said pump.

2. In a fluid proportioning apparatus, the combination of a motor, a pump, a mechanism for connecting said motor and pump including a normally disengaged clutch, electrical control means to intermittently engage said clutch in synchronized response to unit volume flow of fluid in a conduit, means to limit said clutch engagement to a predetermined pump operation and means controlled by said electrical control means to start said motor in synchronized response to the operation of said control means, said means including a time delay means for predetermining the running time interval of said motor for each clutch engagement.

3. The combination with a motorized proportional pump oi an electrical circuit for controlling the operation of said pump, means synchronously responsive to unit volume flow of uid in a conduit to condition said circuit to cause operation of said pump, means synchronized with initiation of the operation of the pump and responsive on completion of unit volume displacement operation of said pump to differently condi.

tion said circuit to effect stoppage of said pump.

4. The combination with a motorized proportional pump of an electrical circuit for controlling the operation of said pump, means synchronously responsive to unit volume flow of iiuid in a conduit to condition said circuit to cause operation of said pump, means synchronized with initiation of the operation of the pump and responsive on completion of unit volume displacement operation of said pump to dilerently condition said circuit to effect stoppage of said pump, said means being interdependently related to cause continuous operation of said pump ata predetermined uid velocity flow in said conduit.

5. In a proportional pump apparatus having a piston, a driven shaft and an intermediate mechanism for driving said piston from said shaft, a power shaft, a normally disengaged clutch between said power shaft and said driven shaft, control means for intermittently engaging said clutch in response to each predetermined unit volume ow in a conduit, and means for conditioning said control means for disengagement during each one revolution of said driven shaft and in the same period of time after each clutch engagement, said means being adapted to cause continuous engagement of said clutch with a predetermined velocity flow in said conduit.

6. In a proportional pumping apparatus, a positive displacement pump, a driven shaft, a transmission between said driven shaft and said pump, a drive shaft, a normally disengaged clutch between said drive'shaft and said driven shaft, electrical means for engaging said clutch for a single cycle operation of said pump with each unit volume flow in a conduit, and means controlled by said clutch for preventing more than one pump cycle with each unit volume ow.

"I. A proportional pump structure comprising a piston pump, a crosshead :in xed operative relation to the piston of said pump, a transverse slot in said crosshead, a bearing block in 'said slot, an unintermitted adjustment for said block in said slot, a driven crank shaft, a connecting rod between said driven shaft and said adjustable block,

a drive shaft, a normally disengaged clutch between said drive shaft and said driven shaft, means to engage and disengage said clutch in accordance with each unit volume flow in a conduit, and means to cause a predetermined pump operation for each unit volume flow.

8. In a proportional pump apparatus having a drive shaft and a driven shaft and a clutch between said shafts, a control means for engaging said clutch for a single cycle of said pump for each unit volume ow in a conduit, a star wheel operable for one step movement for each pump cycle, means operable by said star wheel for conditioning said control means for a succeeding operation, and a timing means associated with said control means for assuring only a single complete pumping cycle with each unit volume ow.

9. The combination with a motor, a pump, a transmission between said motor and pump including a normally disengaged clutch, and electrical means including reversible electrical control connections to intermittently cause engagement of said clutch in accordance with and in response to each unit volume flow of liquid in a conduit, of means normally to limit said pump to one predetermined unit displacement output for each unit volume flow in said conduit irrespective of variations of flow in said conduit, said last means being controlled by said transmisson to reverse the said electrical control connections during each clutch engagement to make said electrical means ineffective until the end of each unit Volume flow.

l0. The combination with a mechanism comprising a motor, a pump, and a transmission between said motor and pump including a normally disengaged clutch, of electrical means to intermittently engage said clutch in accordance with and in response to each unit volume flow of liquid in a conduit, means to retain said clutch engagement for a predetermined pump output, said electrical means being controlled by said mechanism normally to limit said pump to one predetermined unt displacement output for each unit volume flow in said conduit, and means to make said electrical means ineiective during the major portion of said pump displacement.

l1. A proportioning apparatus comprising an intermittently operable pump, control means initiating the operation of said pump for unit displacement in accordance with and in response to each unit volume flow of liquid in a conduit, means for continuing the operation of said pump to complete a predetermined unit displacement. and means controlled by said pump for making said pump control ineiective after each initiated operation and until completion of a pump strokf1` and completion of a succeeding unit volume now in said conduit.

12. The combination of a motor, a pump, a mechanism for connecting said motor and pump including a normally disengaged clutch, and electrical means to intermittently engage said clutch in accordance with each unit volume now of liquid in a conduit, with means operable during each pump stroke to make said electrical means ineffective to cause another pump stroke after each clutch engagement until completion of a succeeding unit volume flow in said conduit, and means for retaining said clutch engaged to complete a pump stroke after said electrical means is made ineective.

13. In a fluid proportioning apparatus, the combination of a normally deenergized electric motor, a pump, a mechanism for connecting said motor and pump including a normally disengaged clutch, control means to intermittently initially engage said clutch and substantially simultaneously start said motorin synchronized response to each unit Volume now of fluid in a conduit, means to make said control means ineiective after engaging said clutch until completion of a pump stroke and completion of another unit volume flow, and means to retain said clutch engaged to complete a pump stroke after said control means is made ineiective.

Y VERL E. MCCOY. 

